/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL SUN MICROSYSTEMS OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: Attributable.java,v 1.1 2005/05/02 17:58:36 hamada Exp $
 */


package net.jxta.document;

import java.util.Enumeration;

/**
 *  Interface for name value pairs to be associated with some base object.
 *
 * @see net.jxta.document.Attribute
 * @see net.jxta.document.StructuredDocument
 * @see net.jxta.document.Element
 *
 **/
public interface Attributable {
    
    /**
     *  Adds an attribute with the given name and value. Some implementations
     *  may support only a single value for each distinct name. Others may
     *  support multiple values for each name. If the value being provided
     *  replaces some other value then that value is returned otherwise null
     *  is returned.
     *
     *  @param  name    name of the attribute.
     *  @param  value   value for the attribute.
     *  @return String  containing previous value for this name if the value
     *                  is being replaced otherwise null.
     **/
    String addAttribute(String name, String value);
    
    /**
     *  Adds an attribute with the given name and value. Some implementations
     *  may support only a single value for each distinct name. Others may
     *  support multiple values for each name. If the value being provided
     *  replaces some other value then that value is returned otherwise null
     *  is returned.
     *
     *  @param  newAttrib    new attribute.
     *  @return String  containing previous value for this name if the value
     *                  is being replaced otherwise null.
     **/
    String addAttribute( Attribute newAttrib );
    
    /**
     *  Returns an enumerations of the attributes assosicated with this object.
     *  Each element is of type Attribute.
     *
     *  @return Enumeration the attributes associated with this object.
     *
     **/
    Enumeration getAttributes( );
    
    /**
     *  Returns a single attribute which matches the name provided. If no such
     *  named attribute exists then null is returned. For impelementations of
     *  this interface which support multiple values for each name only the
     *  first value will be returned. To access all values for a name you must
     *  use getAttributes.
     *
     *  @return Attribute the attributes matching the given name.
     *
     **/
    Attribute getAttribute( String name );
}